Paper tissues sometimes called paper webs or sheets, tissues, tissue layers, paper plies or paper tissue webs, and products made there from, such as paper handkerchiefs, paper kitchen towel or bath tissue, toilet paper or facial tissues, find extensive use in modern society and are well known in the art. Paper tissues are generally made by the layering of cellulose fibers, in a wet form, onto a screen, with the addition of various additives or other ingredients, followed by a drying step. Other process steps, before, during or after the above-mentioned paper making steps are targeted at giving the desired properties to the tissue. Converting steps are aimed at creating a finished product from the paper tissue(s) and can include, for example embossing, lotion application, printing, combining, cutting, perforating, or folding.
Relatively thick and yet soft disposable paper products, namely in the form of paper handkerchiefs, are known. For example, Tempo™, sold by The Procter & Gamble Company, is a multi-ply paper product experienced as thick and soft and having a caliper of about 0.3 mm. A high calliper conveys the idea of high dry and wet strength to the consumer. A high wet strength, also referred to as wet burst strength, in particular prevents tearing or bursting which for a paper handkerchief in turn results in contamination of the user's hand with mucus or other body fluids.
A common way to enhance the smoothness of the tissue surface is to calender the material. Another way to improve the sensation of smoothness perceived by the users of paper tissue products, such as handkerchiefs, is to complement the composition of the paper tissue with some additives during the paper-making phase and/or during the converting phase. Alternatively or additionally, some additives have an effect on the skin of the user touching or using the paper tissue product, e.g. smoothening of the skin or hydration of the skin. Smoothening lotion (also called lotion, softening agent or softening composition in this document) is a generic term to describe those additives which (a) can have a softening effect on the tissue material, (b) preferably an effect on the skin, and (c) are partially transferred onto the skin of the user during use. It is usual industry practice to apply smoothening lotions on a native paper tissue surface at the converting stage of the manufacture of paper tissue products (as opposed to the paper-making stage of the manufacture). Usually, lotions are applied to the external surfaces of the paper tissue, but can also been applied to the internal surfaces. General knowledge on lotions and common application methods can be found in a number of publications. Among those the following are of particular relevance: U.S. Pat. No. 5,525,345, EP 0806157 and WO 02/066740. In WO 98/29605, Vinson et al. describe the application of a smoothening lotion onto a tissue in uniform discrete surface deposits in a configuration that enhances the tactile benefits delivered by the tissue. In WO 97/48854, Trokhan et al. describe a particular topography of the tissue (i.e. elevations) can be combined with a particular application of a lotion (for example on the said elevation) to enhance the softness of the tissue and creates tissue regions with differential properties.
Because smoothening lotions are usually of hydrophobic nature or contain hydrophobic compounds, the presence of the lotion at the surface of the paper tissue can have adverse effects on the properties of the paper tissue. First, the masking of the hydrophilic tissue surface by an hydrophobic lotion can reduce the absorbency of tissue or the speed of absorbency. Second, the lotion can migrate from tissue the surface through the paper tissue structure making the paper tissue less hydrophilic and making less lotion available at the surface to deliver the smoothening benefits to the skin. A traditional way to respond to that expected migration of the lotion over time is to use a relatively high amount of lotion to insure a certain availability of the lotion on the surface of the tissue, even after extended storage. However, this can create an excess of lotion on the freshly produced paper tissues triggering a negative greasy feeling during use (and reducing further more the absorbency of the paper tissue). Third, lotions that are coating the fibers are less likely to be released by the tissue during use and thus, less transferable to the skin of the user. This can be an economic disadvantage due to the relatively high cost of the lotion raw materials.
Accordingly, there is a need to provide a paper tissue exhibiting, preferably concurrently, a relatively high amount of lotion available at the surface of the tissue, and a relatively low amount of lotion in the inner structure of the tissue or tissue product, and a low overall hydrophobicity of the tissue, in order to maintain high absorbency, and a high transferability of the lotion onto the skin of the user, and a relatively low total amount of lotion in/on the tissue.
There is also a need for improved smoothening benefits of the tissue, improved absorbency of paper tissues, and improved transferability of the lotion to the users skin, without having one improvement being detrimental to the other.